Acidic esters of oxyalkylated tetramethylolcyclohexanol



Patented Sept. 15, 1953 ACIDIC ESTERS OF OXYALKYLATED TETRA-METHYLOLCYCLOHEXANOL Melvin De Groote, University City,

to Petrolite Corporation,

ware

Mo., assignor a corporation of Dela- N Drawing. Continuation ofapplications Serial No. 104,801 and Serial No.

104,802, July 14,

1949. This application December 29, 1950, Se-

rial No. 203,534

- 9 Claims.

The present invention is a continuation of my co-pending applicationsSerial Nos. 104,801, now Patent No. 2,552,528, and 104,802, nowabandoned, both filed July 14, 1949.

More specifically, the present invention is concerned with certainacidic esters hereinafter described in detail. Such esters are of valuefor various purposes, and particularly for the resolution of petroleumemulsions of the water-in-oil type. This specific invention i describedin my co-pending application Serial No. 203,533, filed December 29,1950.

The acidic esters which constitute my invention and which arehereinafter described in detail are not only useful for breaking oilfield emulsions, but can be used for other purposes, such as serving asintermediates for further reaction, or for use as break-inducers in thedoctor treatment of sour hydrocarbons, or as components of emulsions,wherein they serve as an emulsifier aid or adjunct, or as a commonsolvent. The acidic esters may be neutralized in various fashions withcompounds varying from triethanolamine to cyclohexylamine, thu yieldingderivatives in which the oil-in-water solubility varies considerablyfrom the original acidic esters themselves. These ester salts soobtained are valuable for the various purposes previously men tioned,such as breaking of petroleum emulsions of the water-in-oil type,emulsion stabilizers, for use as break-inducers in the doctor treatmentof sour hydrocarbons, etc.

In my co-pending applications Serial Nos. 104,801 and 104,802, bothfiled July 14, 1949, I have described, among other things, high molaloxypropylation derivatives of:

(A) High molal oxypropylation derivatives of monomeric polyhydriccompounds with the proviso that (a) The initial polyhydric reactant befree from any radical having at least 8 uninterrupted carbon atoms;

(b) The initial polyhydric reactant have a molecular weight not over1200 and at least 4 hydroxyl radicals;

(c) The initial polyhydric reactant be watersoluble andxylene-insoluble;

(d) The oxypropylation end product be water-insoluble andXylene-soluble;

(e) The oxypropylation end product be within the molecular weight rangeof 2000 to 30,000 on an average statistical basis;

(I) The solubility characteristics of the oxypropylation end product inrespect to water and Xylene be substantially the result of theoxypropylation step;

(,q) The ratio of propylene oxide per hydroXyl in the initial polyhydricreactant be within the range of 7 to (h) The initial polyhydric reactantrepresent not more than 12 by weight, of the oxypropylation end producton a statistical basis;

(2') The preceding provisos being based on complete reaction involvingthe propylene oxide and the initial polyhydric reactant; and

(B) Polycarboxy reactants, and with the further proviso that the ratioof polycarboxy reactant to hydroxylated reactant be in the molarproportion of one mole of polycarboxy reactant for each hydroxyl presentin the alcoholic reactant.

The co-pending application above referred to. i. e., Serial No. 104,802,filed July 14, 1949, is concerned with the new derivatives as suchwithout limitation as to any particular use.

The aforementioned co-pending applications included at least onecompound, which, although not strictly within the limits defined, stillpossessed the same distinctive and valuable properties, i. e.,oxypropylation derivative of 2-2-6-6- tetramethylolcyclohexanol. Thisproduct is made by General Mills, Inc., Minneapolis, Minnesota. Forconvenience and brevity, it is referred to in the trade, and isdescribed by the manufacturer, as TMC. Hereafter, reference will eitherbe made to TMC or tetramethylolcyclohexanol.

The present invention is concerned with a fractional ester obtained froma polycarboxy acid and a pentalol, i. e., a chemical compound having 5alkanol hydroxyls or the equivalent comparable to diols, triols, andtetralols. The particular hydroxylated compound herein employed isobtained by the oxypropylation of TMC or the simple ethers of TMC(tetramethylolcyclohexanol) by treating said compound with l to 10 molesof ethylene oxide or butylene oxide, or a mixture thereof. All suchderivatives are characterized by having 5 terminal hydroxyl radicals.

TMC is depicted thus:

on H Homo onion HOHSO l H2 H:

the oxypropylation derivatives can be indicated thus:

R'[O(RO) 111-115 wherein n is a number almost invariably more than oneand may be as much as 25 or 30 or more with 10 to 20 as being arepresentative value. As will be pointed out hereinafter, whenthemolecular weight of such oxypropylation derivatives on the average reach3,000 or more, based on the hydroxyl value, the product is at leastemulsifiable in kerosene, and frequently, and often not infrequently,perfectly soluble in kerosene. This is the preferred type of material,and particularly with the further proviso that the molecular weight,based on the hydroxyl value, be between 3,000 and 5,000.

As has been pointed out previously, in a generic sense, the inveintioninvolves the ethers obtained by use of ethylene oxide, butylene oxide,etc., as well as TMC itself.

If one indicates a polycarboxy acid in the following manner:

coon

in which R" is the radical of a polycarboxy acid, as indicated, andwhich is preferably free from any radicals having more than 8uninterrupted carbon atoms in a single group, and n is a whole numbernot greater than 2.

If one mole of the oxypropylated derivative previously described by theformula:

is esterified with a polycarboxy acid, as previously described, in theratio of moles of the polycarboxy acid or equivalent for each mole ofoxypropylated TMC, then the acidic fractional ester so obtained can beindicated by the following formula:

1? 1 R'[O(RO),.CR(COOH),.' 5

in which the various characters have their previous significance.

Such compound, of course, does not define the invention in its mostgeneric aspect, for the obviclass of ethylene oxide and butylene oxidein the ratio of 1 to 10 moles of the oxide for each mole oftetramethylolcyclohexanol, with the proviso that the oxypropylatedcompound, prior to esterification, have a molecular weight within therange of 1,500 and 6,000. Preferably, the pentahydroxylated compoundshould be at least emulsifi-able in kerosene. The oxypropylated TMC orTMC compound may be used, even though it is kerosene-insoluble, i. e.,even though its molecular weight is in' the low range, for instance, intheneighborhood of 1,500 to 1,750.

Furthermore, it is preferred that the polycarboxy acid have not over 8carbon atoms. The acidic fractional esters above described are obtainedby reacting 5 moles of the polycarboxy reactant with one mole of thepentahydroxylated reactant.

For convenience, what is said hereinafter will be divided into threeparts:

Part 1 is concerned with the oxypropylation oftetramethylolycyclohexanol. The same procedure, of course, would beapplicable to the hydroxylated ethers above described. In fact, theethers can be prepared in the same manner from tetramethylolcyclohexanolby use of ethylene oxide or butylene oxide, or a mixture;

Part 2 is concerned with the preparation of the acidic fractional estersfrom the aforementioned pentalols, i. e., the pentahydroxylatedcompounds obtained as described in Part 1; and

Part 3 is concerned with other derivatives valuable for various purposesincluding demulsification but not specifically claimed in the instantapplication.

PART 1 For a number of well known reasons equipment, whether laboratorysize, semi-pilot plant size, pi10t plant size, or large scale size, isnot, as a rule, designed for a particular alkylene oxide. Invariably,and inevitably, however, or particularly in the case of laboratoryequipment and pilot plant size, the design is such as to use any of thecustomarily available alkylene oxides, i. e., ethylene oxide, propyleneoxide, butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. Inthe subsequent description of the equipment it becomes obvious that itis adapted for oxyethylation as well as oxypropylation.

Oxypropylations are conducted under a wide variety of conditions, notonly in regard to presence or absence of catalyst, and the kind ofcatalyst, but also in regard to the time of reaction, temperature ofreaction, speed of reaction, pressure during reaction, etc. Forinstance, oxyalkylations can be conducted at temperatures up toapproximately 200 C. with pressures in about the same range up to about200 pounds per square inch. They can be conducted also at temperaturesapproximating the boiling point of water or slightly above, as, forexample, to C. Under such circumstances, the pressure will be less than30 pounds per square inch, unless some special procedure is employed, asis sometimes the case, to wit, keeping an atmosphere of inert gas suchas nitrogen in the vessel during the reaction. Such low-temperaturelow-reaction rate oxypropylations have been described very completely inU. S. Patent No. 2,448,664, to H. R. Fife et al., dated September 7,1948. Low-temperature low-pressure Oxypropylations are particularlydesirable where the compound being subjected to oxypropylation containsone, two, or three points of reaction only, such as monohydric alcohols,glycols and triols.

Since low-pressure low-temperature reaction speed Oxypropylationsrequire considerable time, for instance, 1 to 7 days of 24 hours each tocomplete the reaction, they are conducted, as a rule, whether on alaboratory scale, pilot plant scale, or large scale, so as to operateautomatically. The prior figure of seven days applies especially tolarge-scale operations. I have used conventional equipment with twoadded automatic features:

(a) A solenoid-controlled valve which shuts oil the propylene oxide inevent that the temperature gets outside a predetermined and set range,for instance, 95 to 120 0.; and

(1)) Another solenoid valve, which shuts off the propylene oxide (or forthat matter ethylene oxide if it is being used) if the pressure getsbeyond a predetermined range, such as to pounds.

Otherwise, the equipment is substantially the same as is commonlyemployed for this purpose where the pressure of reaction is higher,speed of reaction is higher, and time of reaction is much shorter. Insuch instances such automatic controls are not necessarily used.

Thus, in preparing the various examples I have found it particularlyadvantageous to use laboratory equipment or pilot plant which isdesigned to permit continuous oxyalkylation, whether it beoxypropylation or oxyethylation. With certain obvious changes, theequipment can be used also to permit oxyalkylation involving the use ofglycide where no pressure is involved, except the vapor pressure of asolvent, if any, which may have been used as a diluent.

As previously pointed out, the method of using propylene oxide is thesame as ethylene oxide. This point is emphasized only for the reasonthat the apparatus is so designed and constructed as to use eitheroxide.

The oxypropylation procedure employed in the preparation of theoxyalkylated derivatives has been uniformly the same, particularly inlight of the fact that a continuous automatically-controlled procedurewas employed. In this procedure the autoclave was a conventionalautoclave made of stainless steel and having a capacity of approximately15 gallons and a working pressure of one thousand pounds gauge pressure.This pressure obviously is far beyond any requirement as far aspropylene oxide goes, unless there is a reaction of explosive violenceinvolved due to accident. The autoclave was equipped with theconventional devices and openings, such as the variable-speed stirreroperating at speeds from R. P. M. to 500 R. P. M.; thermometer well andthermocouple for mechanical thermometer; emptying outlet; pressuregauge, manual vent line; charge hole for initial reactants; at least oneconnection for introducing the alkylene oxide, such as propylene oxideor ethylene oxide,

to the bottom of the autoclave; along with suitable devices for bothcooling and heating the autoclave, such as a cooling jacket, andpreferably, coils in addition thereto, with the jacket so arranged thatit is suitable for heating with steam or cooling with water and furtherequipped with electrical heating devices. Such autoclaves are, ofcourse, in essence, small-scale replicas of the usual conventionalautoclave used in oxyalkylation procedures. In some instances, inexploratory preparations an autoclave having a smaller capacity, forinstance, approximately 3 liters in one case and about 1% gallons inanother case, was used.

Continuous operation, or substantially continuous operation, wasachieved by the use of a separate container to hold the alkylene oxidebeing employed, particularly propylene oxide. In conjunction with thesmaller autoclaves, the container consists essentially of a laboratorybomb having a capacity of about one-half gallon, or somewhat in excessthereof. In some instances, a larger bomb was used, to wit, one having acapacity of about one gallon. This bomb was equipped, also, with aninlet for charging, and an eductor tube going to the bottom of thecontainer so as to permit discharging of alkylene oxide in the liquidphase to the autoclave. A bomb having a capacity of about 60 pounds wasused in connection with the l5-gallon autoclave. Other conventionalequipment consists, of course, of the rupture disc, pressure gauge,sight feed glass, thermometer connection for nitrogen for pressuringbomb, etc. The bomb was placed on a scale during use. The connectionsbetween the bomb and the autoclave were flexible stainless steel hose ortubing so that continuous weighings could be made without breaking ormaking any connections. This applies also to the nitrogen line, whichwas used to pressure the bomb reservoir. To the extent that it wasrequired, any other usual conventional procedure or addition whichprovided greater safety was used, of course, such as safety glass,protective screens, etc.

Attention is directed again to what has been said previously in regardto automatic controls, which shut off the propylene oxide in eventtemperature of reaction passes out of the predetermined range, or ifpressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations becomeuniform, in that the reaction temperature was held within a few degreesof any selected point, for instance, if C. was selected as the operatingtemperature the maximum point would be at the most C. or 112 C., and thelower point would be 95 or possibly 98 C. Similarly, the pressure washeld at approximately 30 pounds within a 5-pound variation one way orthe other, but might drop to practically zero, especially where nosolvent such as xylene is employed. The speed of reaction wascomparatively slow under such conditions as compared with oxyalkylationsat 200 C. Numerous reactions were conducted in which the time variedfrom one day (24 hours) up to three days ('72 hours), for completion ofthe final member of a series. In some instances, the reaction may takeplace in considerably less time, i. e., 24 hours or less, as far as apartial oxypropylation is concerned. The minimum time recorded was abouta 3-hour period in a single step. Reactions indicated as being completein 10 hours may have been complete in a lesser period of time in lightof the automatic equipment employed. This applies also where thereactions were complete in a shorter period of time, for instance, 4 to5 hours. In the addition of propylene oxide, in the autoclave equipmentas far as possible the valves were set so all the propylene oxide, iffed continuously, would be added at a rate so that the predeterminedamount would react within the first 15 hours of the 24-hour period ortwothirds of any shorter period. This meant that if the reaction wasinterrupted automatically for a period of time for pressure to drop ortemperature to drop, the predetermined amount of oxide would still beadded, in most instances, well within the predetermined time period.Sometimes where the addition was a comparatively small amount in a10-hour period, there would be an unquestionable speeding up of thereaction, by simply repeating the examples and using 3, 4, or 5 hoursinstead of 10 hours.

When operating at a comparatively high temperature, for instance,between to 200 C., an unreacted alkylene oxide such as propylene oxide,makes its presence felt in the increase in pressure, or the consistencyof a higher pressure.

However, at a low enough temperature it may happen that the propyleneoxide goes in as a liquid. If so, and if it remains unreacted, there is,of course, an inherent danger and appropriate steps must be taken tosafe-guard against this possibility; if need be, a sample must bewithdrawn and examined for unreacted propylene oxide. One obviousprocedure, of course, is to oxypropylate at a modestly highertemperature, for instance, at 140 to 150 C. Unreacted oxide afiectsdetermination of the acetyl or hydroxyl value of the hydroxylatedcompound obtained.

The higher the molecular weight of the compound, i. e., towards thelatter stages of reaction, the longer the time required to add a givenamount of oxide. One possible explanation is that the molecule, beinglarger, the opportunity for random reaction is decreased. Inversely, thelower the molecular weight, the faster the reaction t-akes place. Forthis reason, sometimes at least, increasing the concentration of thecatalyst does not appreciably speed up the reaction, particularly whenthe product subjected to oxyalkylation has a comparatively highmolecular weight. However, as has been pointed out previously, operatingat a low pressure and a low temperature, even in large scale operations,as much as a week or ten days time may lapse to obtain some of thehigher molecular weight derivatives from monohydric or dihydricmaterials.

In a number of operations the counterbalance scale or dial scale holdingthe propylene oxide bomb was so set that when. the predetermined amountof propylene oxide had passed into the reaction, the scale movementthrough a time operating device was set for etither one to two hours, sothat reaction continued for l to 3 hours after the final addition of thelast propylene oxide, and thereafter the operation was shut down. Thisparticular device is particularly suitable for use on larger equipmentthan laboratory size autoclaves, to wit, on semi-pilot plant or pilotplant size, as well as on large scale size. This final stirring periodis intended to avoid the presence of unreacted oxide.

In this sort of operation, of course, the temperature range wascontrolled automatically by either use of cooling water, steam, orelectrical heat, so as to raise or lower the temperature. The pressuringof the propylene oxide into the reaction vessel was also automaticinsofar that the feed stream was set for a slow continuous run which wasshut off in case the pressure passed a predetermined point, aspreviously set out. All the points of design, construction, etc., wereconventional, including the gases, check valves and entire equipment. Asfar as I am aware, at least two firms, and possibly three, specialize inautoclave equipment such as I have employed in the laboratory, and areprepared to furnish equipment of this sam kind. Similarly, pilot plantequipment is available. This point is simply made a precaution in thedirection of safety. Oxyalkylations, particularly involving ethyleneoxide, glycide, propylene oxide, etc., should not be conducted except inequipment specifically designed for the purpose.

Example 1a The starting material was a commercial grade oftetramethylolcyclohexanol. The particular autoclave employed was onewith a capacity of 15 gallons, or on the average of 120 pounds ofreaction mass. The speed of the stirrer could be 8 varied from to 350 R.P. M. Approximately 8.6 pounds of tetramethylolcyclohexanol were chargedinto the autoclave along with .82 pound of caustic soda. The reactionpot was flushed out with nitrogen. The autoclave was sealed and theautomatic devices adjusted for injecting 58.2 pounds of propylene oxidein approximately 10 hours. The pressure was set for a maximum of 35pounds per square inch. This meant that the bulk of the reaction couldtake place, and probably did take place, at a lower pressure. Thecomparatively low pressure was the result of the fact that considerablecatalyst was present and also the reaction time was fairly long. Thepropylene oxide was added comparatively slowly, and more important, theselected temperature range was 205" to 215 F. (approximately the boilingpoint of water). The initial introduction of propylene oxide was notstarted until the heating devices had raised the temperature to aboutthe boiling point of water. At the completion of the reaction a samplewas taken and oxypropylation proceeded as described in Example 2a,following.

Example 2a Approximately 59.7 pounds of reaction mass identified asExampl la, preceding, were permitted to remain in the reaction vessel,and, without the addition of any more catalyst, 43.02 pounds ofpropylene oxide were added. The oxypropylation was conducted insubstantially the same manner with regard to pressure and temperature,as in Example 111., preceding, except that the reaction was complete insomewhat less time, i. e., 8 hours instead of 10 hours. At the end ofthe reaction period part of the reaction mass was withdrawn and employedas a sample, and oxypropylation was continued with the remainder of thereaction mass, as described in Example 3, following.

Example 3a 63.76 pounds of the reaction mass identified as Example 2a,preceding, were permitted to remain in the reaction vessel. oxide wereintroduced in this third stage. No additional catalyst was added. Thetime period was the same as in Example 2a, preceding, to wit, 8 hours.The conditions of temperature and pressure were substantially the sameas in Example 1a, preceding.

At the completion of the reaction, part of the reaction mass waswithdrawn and the remainder subjected to further oxypropylation, asdescribed in Example 4a,'following.

Example 4a '78 pounds of the reaction mass identified as Example 3a,preceding, were permitted to remain in the autoclave. Without adding anymore catalyst, this reaction mass was subjected to furtheroxypropylation as in the preceding examples. The amount of propyleneoxide added as 11.25 pounds. Conditions in regard to temperature andpressure were substantially the same as in Example 1a, preceding. At theend of the reaction period, part of the sample was withdrawn and theremainder of the reaction mass was Subjected to further oxypropylation,as described in Example 5a, following.

Example 5a Approximately 61.75 pounds of the reaction mass werepermitted to stay in the autoclave. No additional catalyst wasintroduced. 17.12 pounds of propylene oxide were added in a -5- 22.5pounds of propylene hour period. The conditions of reaction in regard totemperature and pressure were substantially the same as in Example 111,preceding.

Example 6a Approximately 70.87 pounds of the reaction mass werepermitted to stay in the autoclave. No additional catalyst wasintroduced. 22.82 pounds of propylene oxide were added. In thisparticular instance the addition was very slow, due to the lowconcentration of catalyst. The time required was 14 hours. Theconditions in regard to temperature and pressure were substantially thesame as in Example 1 preceding.

In this particular series of examples, the oxypropylation was stopped atthis stage. In other series I have continued the oxypropyla tion so thatthe theoretical molecular weight was approximately 9,00010,000 and thehydroxyl molecular weight ranged from 6,000 to 7,000. Other weights, ofcourse, are obtainable using the same procedure.

Needless to say, the procedure employed to produce oxypropylatedderivatives can be employed also to produce oxyethylated derivatives andoxybutylated derivatives of the kind previously described. .Suchderivatives obtained by treating 'IMC with l to moles of butylene oxide,or a mixture of the two, can then be subjected to oxypropylation in thesame manner as illustrated by previous examples so as to yield productshaving the same molecular weight characteristics and the same solubilityor emulsifiability in kerosene.

What is said herein is presented in tabular form in Table I, immediatelyfollowing, with some added information as to molecular weight and as tosolubility of the reaction product in water, xylene and kerosene.

Example 5a, one would have expected a value of approximately 4700 andthe value obtained was somewhat less. The value of Example 6a seems tobe perfectly normal. An oxypropylation of this kind has been repeated,and in a number of instances, in fact, in the majority of instances, thevalues came through perfectly normal, for instance, as shown by thefollowing table. Figures showing only the theoretical molecular Weightand the hydroxyl molecular weight would give similar oxypropylations.However, not infrequently ultimate erratic results of the above kindhave been obtained in connection with TMC. No satisfactory explanationis offered. A more normal oxypropylation might show values as follows:

Theoretical Molec. Wt. Weight Another explanation Which has sometimesappeared in the oxypropylation of nitrogencontaining compoundsparticularly such as acetamide, is that the molecule appears todecompose under conditions of analysis and unsaturation seems to appearsimultaneously. One suggestion has been that one hydroxyl is lost bydehydration and that this ultimately causes a break in the molecule insuch a way that two new hydroxyls are formed. This is shown after TABLEI M. W. by Max- TMO Oxide Cata- Theo. TMC Oxide Crta Ex. No. Amt, Amt,lyst, Mol. Amt, Amt, lyst, gg- ,gfgg; E?" gi f lbs. lbs. lbs. Wt. lbs.lbs. term a F. in. in.

Ordinarily in oxypropylation, the hydroxyl value molecular weight is aptto approximate the theoretical molecular weight based on complete nessof reaction, if oxypropylation is conducted slowly and at acomaparatively low temperature, as described. In this instance, this wastrue almost up to approximately 3,000. Note, however, that a variationappears in the oxypropylation of TMC, which is exceptional. The hydroxymolecular weights were slightly higher in the case of Examples 1a and 2athan the theoretical molecular Weights. One explanation which has beenoffered, is that one of the hydrogen atoms is liable enough to permitoxypropylation taking place by breaking the bond between a carbon atomand a hydrogen atom. This does take place perhaps in a few peculiarcompounds having unusual structure, but would not be expected in thisinstance. Note also that in the instance of hydroxyl molecular weight ofa fashion in following way:

In the above formulas the large X is obviously not intended to signifyanything except the central part of a large molecule, whereas, as far asa speculative explanation is concerned, one need only consider theterminal radicals, as shown. Such suggestion is of interest only becauseit may be a possible explanation of how an increase in hydroxyl valuedoes take place which could be interpreted as a decrease in molecularweight. This matter is considered subsequently in the final paragraphsof the next part, i. e., Part 2.

When acidic esters were prepared from an oxypropylation showing normalvalues and also from an oxypropylation showing abnormal values to theextent illustrated by the above table, one could not detect anyparticular difference in demulsifying effect based on the same hydroxylvalue molecular eight.

Referring again to Table I, Examples 1a, through 6a werewater-insoluble. Examples 1a through 6a were xylene-soluble. Examples laand 2a were insoluble in kerosene and Example 3a showed a very definitetendency to emulsify in kerosene and subsequent Examples 4a through 6awere soluble to emulsifiable in kerosene.

The final products at the end of the oxypropylation step, were somewhatviscous liquids, more viscous than ordinary polypropylene glycols, witha slight amber tint. This color, of course, could be removed, ifdesired, by means of bleaching clays, filtering chars, or the like. Theproducts were slightly alkaline, due to the residual caustic soda. Theresidual basicity, due to the catalyst, would be the same if sodiummethylate had been employed.

Needless to say, there is no complete con-version of propylene oxideinto the desired hydroxylated compounds. This is indicated by the factthat the theoretical molecular weight, based on a statistical average,is greater than the molecular weight calculated by usual methods, onbasis of acetyl or hydroxyl value. This is true even in the case of anormal run of the kind noted previously. It is true also in regard tothe oxypropylation of simple compounds, for instance,

pentaerythritol, sorbitol, or the like, which do not show the abnormalcharacteristics sometimes noted in the oxypropylation of TMC".

Actually, there is no completely satisfactory method for determiningmolecular weights of these types of compounds with a high degree ofaccuracy when the molecular weights exceed 2,000. In some instances, theacetyl value or hydroxyl value serves as satisfactorily as an index tothe molecular weight as any other procedure, subject to the abovelimitations, and especially in the higher molecular weight range. If anydifficulty is encountered in the manufacture of the esters as describedin Part 2, the stoichiometrical amount of acid or acid compound shouldbe taken which corresponds to the indicated acetyl or hydroxyl value.This matter has been discussed in the literature and is a matter ofcommon knowledge and requires no further elaboration. In fact, it isillustrated by some of the examples appearing in the patent previouslymentioned.

PART 2 As previously pointed out, the present invention is concernedwith acidic esters obtained from the oxypropylated derivatives describedin Part 1,

immediately preceding, and polycarboxy acids, particularly dicarboxyacids such as adipic acid, phthalic acid, or anhydride, succin-ic acid,diglycollic acid, sebacic acid, azeleic acid, aconitic acid, maleic acidor anhydride, citracon-ic acid or anhydride, maleic acid or anhydrideadducts, as obtained by the Diels-Alder reaction from products such asmaleic anhydride, and cyclopentadiene. Such acids should be heat-stableso they are not decomposed during esterification. They may contain asmany as 36 carbon atoms, as, for example, the acids obtained bydimerization of unsaturated fatty acids, unsaturated monocarboxy fattyacids, or unsaturated monocarboxy acids having 18 carbon atoms.Reference to the acid in the hereto appended claims obviously includesthe anhydrides or any other obvious equivalents. My preference, however,is to use polycarboxy acids having not over 8 carbon atoms.

The production of esters including acid esters (fractional esters) frompolycarboxy acids and glycols or other hydroxylated compounds is wellknown. Needless to say, various compounds may be used such as the lowmolal ester, the anhydride, the acyl chloride, etc. However, for purposeof economy, it is customary to use either the acid or the anhydride. Aconventional procedure is employed. On a laboratory scale one can employa resin pot of the kind described in U. 5. Patent No. 2,499,370, datedMarch '7, 1950, to De Groote and Keiser, and particularly with one moreopening to permit the use of a porous spreader, if hydrochloric acid gasis to be used as a catalyst. Such device or absorption spreader consistsof minute Alundum thimbles which are connectedto a glass tube. One canadd a sulfonic acid such as para-toluene sulfonic acid as a catalyst.There is some objection to this because in some instances there is someevidence that this acid catalyst tends to decompose or rearrange theoxypropylated compounds, and particularly likely to do so if theesterification temperature is too high. In the case of polycarboxy acidssuch as diglycollic acid, which is strongly acidic, there is no need toadd any catalyst. The use of hydrochloric gas has one advantage overpara-toluene sulfonic acid, and that is, that at the end of thereaction, it can be removed by flushing out with nitrogen, whereas,there is no reasonably convenient means available of removing thepara-toluene sulfonic acid or other sulfonic acid employed. Ifhydrochloric acid is employed, one need only pass the gas through at anexceedingly slow rate so as to keep the reaction mass acidic. Only atrace of acid need be present. I have employed hydrochloric acid gas orthe aqueous acid itself to eliminate the initial basic material. Mypreference, however, is to use no catalyst whatsoever and to insurecomplete dryness of the hydroxylated compound, as described in the finalprocedure just preceding Table II.

The products obtained in Part 1, preceding, may contain a basiccatalyst. As a general procedure, I have added an amount ofhalf-concentrated hydrochloric acid considerably in excess of what isrequired to neutralize the residual catalyst. The mixture is shakenthoroughly and allowed to stand overnight. It is then filtered andrefluxed with the xylene present until the water can be separated in aphase-separating trap. As soon as the product is substantially free fromwater the distillation stops. This preliminary step can be carried outin the flask to be used for esterification. If there is any furtherdeposition of sodium chloride during the reflux stage, needless to say,a second filtration may be required. In any event, the neutral orslightly acidic solution of the oxypropylated derivatives described inPart 1 is then diluted further with sufficient xylene, decalin,petroleum solvent, or the like, so that one has obtained approximately a65% solution. To this solution there is added a polycarboxylatedreactant, as previously described, such as phthalic' anhydride. succinicacid, or anhydride, diglycollic acid, etc. The mixture is refluxed untilesterification is complete, as indicated by elimination of Water or dropin carboxy1 value. Needless to say, if one produces a half-ester from ananhydride such as phthalic anhydride, no water is eliminated. However,if it is obtained from diglycollic acid, for example, water iseliminated. All such procedures are conventional and have been sothoroughly described in the literature that further consideration willbe limited to a few examples and a comprehensive table.

Other procedures for eliminating the basic residual catalyst, if any,can be employed. For example, the oxyalkylation can be conducted inabsence of a solvent or the solvent removed after oxypropylation. Suchoxypropylation end product can then be acidified with just enoughconcentrated hydrochloric acid to just neutralize the residual basiccatalyst. To this product one can then add a small amount of anhydroussodium sulfate (sufficient in quantity to take up any water that ispresent) and then subject the mass to centrifugal force so as toeliminate the hydrated sodium sulfate and probably the sodium chlorideformed. The clear, somewhat viscous, straw-colored amber liquid soobtained may contain a small amount of sodium sulfate or sodiumchloride, but in any event, is perfectly acceptable for esterificationin the manner described.

It is to be pointed out that the products here described are notpolyesters in the sense that there is a plurality of both hydroxylatedcompound radicals and acid radicals; the product is characterized byhaving only one hydroxylated In some instances, and in fact, in manyinstances, I have found that in spite of the dehydration methodsemployed above, that a mere trace of water still comes through and thatthis mere trace of water certainly interferes with the acetyl orhydroxyl value determination, at least when a number of conventionalprocedures are used and may retard esterification, particularly wherethere is no sulfonic acid or hydrochloric acid present as a catalyst.Therefore, I have preferred to use the following procedure: I haveemployed about 200 grams of the hydroxylated compound, as described inPart 1, preceding; I have added about 200 gr. of benzene, and thenrefluxed this mixture in the glass resin pot, using a phase-separatingtrap until the benzene carried out all the water present as water ofsolution or the equivalent. Ordinarily this refluxing temperature is aptto be in the neighborhood of 130 to possibly 150 C. When all this wateror moisture has been removed, I also withdraw approximately 20 grams ora little less benzene and then add the required amount of the carboxyreactant and also about 150 grams of a high boiling aromatic petroleumsolvent. These solvents are sold by various oil refineries, and, as faras solvent efiect, act as if they were almost completely aromatic incharacter. Typical distillation data in the particular type I haveemployed and found very satisfactory is the following:

L. B. 1=., 142 0. ml., 242 0. 5 ml., 200C. ml., 244 0. 10 ml,, 209 0.ml., 248 0. 15 ml., 215 0. ml., 252 c. 20 ml., 216 0. m1., 252 0. 25ml., 220 0. ml., 260 0. 20 ml., 225C. ml., 264 0. 35 ml., 230 0. m1, 2700. 40 ml., 234 0. ml., 280 0. 45 ml., 237 0. ml., 307C.

After this material is added, refluxing is continued, and, of course, isat a high temperature, to wit, about to C. If the carboxy reactant is ananhydride, needless to say, no water of reaction appears; if the carboxyreactant is an acid water of reaction should appear and should beeliminated at the above reaction temperature. If it is not eliminated, Isimply separate out another 10 to 20 cc. of benzene by means of thephase-separating trap, and thus raise the temperature to or C., or evento 200 C., if need be. My preference is not to go above 200 C.

The use of such solvent is extremely satisfactory, provided one does notattempt to remove the solvent subsequently, except by vacuumdistillation, and provided there is no objection to a little residue.Actually, when these materials are used for a purpose such asdemulsification, the solvent might just as well be allowed to remain. Ifthe solvent is to be removed by distillation, and particularly vacuumdistillation, then the high boiling aromatic petroleum solvent mightWell be replaced by some more expensive solvent, such as decalin or onalkylated decalin which has a rather definite or close range boilingpoint. The removal of the solvent, of course, is purely a conventionalprocedure and requires no elaboration.

In the appended table Solvent #7-3, which appears in all instances, is amixture of 7 volumes of the aromatic petroleum solvent previouslydescribed and 3 volumes of benzene. This was used, or a similar mixture,in the manner previously described. In a large number of similarexamples decalin has been used, but it is my preference to use the abovementioned mixture, and particularly with the preliminary step ofremoving all the water. If one does not intend to remove the solvent, mypreference is to use the petroleum solvent-benzene mixture, althoughobviously, any of the other mixtures, such as decalin and xylene, can beemployed.

The data included in the subsequent tables, i. e., Tables II and III,are self-explanatory, and very complete, and it is believed no furtherelaboration is necessary.

TABLE II Mol.

Amt. Amt. of Ex. Theo Theo. Actual wt. Ex. No. 01 polycarof acid N of Mhvydmx based hyd. Polycarboxy reactant boxy reester a HMO g e dmxkyl i 1cmpd. actant C1111) V8 U0 (grs') 1a 1, 705 162.5 171 1, 740 196Diglycollic acid 75.5 1a 1,705 102.5 171 1, 740 196 Plltbalicanhydride83.3 la 1, 705 162. 171 1, 740 199 lllcleic anhydridc 55. 9 la 1,705102.5 171 1,740 192 11001110102013... 97.5 111 1,705 102.5 171 1,740 200itraconic anhydri c 64.5 2,950 95.2 90 3,110 199 Diglycollic acid 42.920 2,950 95.2 90 3,110 199 Phtlialic anhydridc 47.4 22 2,950 95.2 903,110 202 1\la1e1canhydride 31.8 20 2,950 95.2 90 3,110 201 14 0111110acid 40.5 22 2,950 95.2 90 3,110 203 Citraconic anhydride 36.4 20 3,94075.2 31.0 3,430 203 Diglyccllic acid 33.0 3,940 75.2 31.0 3,430 199Phthalic 51111 01105" 42.9 32 3, 940 75.2 81.6 3, 430 200 Maleicanydride... 28.6 30 3,940 75.2 31.0 3, 430 199 40011101011010 50.5 3113, 940 75.2 31.0 3,430 199 32.5 4,500 02.3 75.5 3,810 200 35.2 40 4.,500 02.3 75.5 3,310 199 33.5 4a 4, 500 02.3 75.5 3,310 201 253 4a 4, 50002.3 75.5 3, 310 194 11 0111110 acid 444 4a 4,500 02.3 75.5 3,810 195C1traconicanl1ydride 28.0 5, 770 48.6 75.5 3,710 211 Diglycollic acid37.8 511 5,770 48.6 75.5 3, 710 201 P11th a1ica1111ydride 40.0 50 5,71048.6 75.5 3,710 201 Maleic anhydride 26.4 511 5, 770 48.6 75.5 3, 710200 Aconitic acid 47.0 50 5,770 48.6 75.5 3,710 200 C tracomcanhydridem. 30.2 7, 640 36.8 53.8 5, 200 205 Diglycollic acid 26.2 007,040 30.3 55.3 5, 200 205 Phthal1canl1ydride 29.0 611 7, 640 36.8 53.85, 200 203 Malcic anhyd1ide 19.2 60 7,740 30.3 53.3 5,200 2031100111005010 34.0 00 7, 040 30.3 53.5 5, 200 203 01010501115 anhydride.21.3

TABLE III 30 dium sulfate is not precipitating out. Such salt should beeliminated, at least for exploration ex- E I perimentation, and can beremoved by filtering. Amt Water E t 1 b 1 Ex. No. of Solvent solvmitficat1on estcrifiout very 6 S8 emg equa 875 the Size Of the a te (Us) ,33 g (w) molecule increases and the reactive hydroxyl 35 radicalrepresents a smaller fraction of the en- 252 147 5% 12 2 tire molecule,more difficulty 1s involved in ob- 07-3 279 101 7 1, 0 taimng completeesterification.

3S3 g g Even under the most carefully controlled con- #7-3 205 135 2% Nd1t1ons of oxypropylation involving comparative- ,liyz 1y lowtemperatures and long time of reaction, #73 234 105 4 None there areformed certain compounds whose comfi g g g g positions are stillobscure. Such side reaction #7-3 241 143 3 T .7 products can contributea substantial proportion if; 2 2 1,332 of the final cogeneric reactionmixture. Various #7-3 245 17s 3% 5.4 suggestions have been made as tothe nature of 1% $3 it: ffg these compunds, such as being cyclicpolymers of #7-3 233 143 4% 130110 propylene oxide, dehydration productswith the $3.2 1% 2 appearance of a vinyl radical, or isomers of #7-3 223134 3 Noang propylene oxide or derivatives thereof, 1. e., of an $31232% 5% Nm'le 5Q aldehyde, ketone, or allyl alcohol. In some infig-g 9 011 stances, an attempt to react the stoichiometric 1 230 152 2 Noneamount of a polycarboxy acid with the oxyg-g 3% 5 propylated derivativeresults in an excess of the 220 136 5% None carboxylated reactant, forthe reason that apfg-g 3 12% g 3 51 parently under cond1tions ofreaction less reactive hydroxyl radicals are present than indicated bythe hyroxyl value. Under such circumstances, The procedure fomanufacturing th esters there is simply a residue of the carboxylicreachas been illustrated by preceding examples. If, tant which can beremoved by filtration, or, if for any reason, reaction does not takeplace in a desired, the esterification procedure can be remanner that isaccept bl attention Should be peated, using an appropriately reducedratio of directed to the following deta11s: carboxylic reactant.

(a) Recheck the hYd O YI acetyl Value of Even the determination of thehydroxyl value the o yp y m y mines of kind and conventional procedureleaves much to be specified, and use a stolchiometrically equivalentdesired due either to the cogeneric materials amount of acid previouslyreferred to, or, for that matter, the

(b) If the Teactlon does not proceed Wlth presence of any inorganicsalts or propylene oxsonable speed, either raise the temperature inid Obt of th tim u V 011S1y, this oxide should be el1m111ated. (heated orelse extend he penod e e p 1- The solvent employed, if any, can beremoved to 12 or 16 hours, if need be; 1

(c) If necessary, use 1/2% of paratoluene from the finished ester bydistillation, and parionic acid or some other acid as a catalyst; andtlcularly vacuum distillation. The final products (d) If theesterification does not produce or liquids are generally from almostwater white clear product, a check should be made to see if or palestraw to a light amber in color, and show an inorganic salt such assodium chloride or moderate viscosity. They can be bleached with Oneneed not point out the products obtained as intermediates, i. e., theoxypropylation products, can be subjected to a number of other reactionswhich change the terminal groups, as, for example, reaction of ethyleneoxide, butylene oxide, glycide, epichlorohydrin, etc. Such productsstill having residual hydroxyl radicals can again be esterified with thesame polycarboxy acids described in Part 2 to yield acidic esters,which, in turn, are suitable as demulsifying agents.

Furthermore, such hydroxylated compounds obtained from thepolyoxypropylated materials described in Part 2, or, for that matter,the very same oxypropylated compounds described in Part 2 withoutfurther reaction, can be treated with a number of reactive materials,such as dimethyl sulfate, sulfuric acid, ethylene imine, etc., to yieldentirely new compounds. If treated with maleic anhydride,monochloroacetic acid, epichlorohydrin, etc., one can prepare furtherobvious variants by (a) reacting the maleic acid ester afteresterification of the residual carboxyl radical with sodium bisulfite soas to give a sulfosuccinate. Furthermore, derivatives having a labilechlorine atom such as those obtained from chloroacetic acid orepichlorohydrin, can be reacted with a tertiary amine to give quaternaryammonium compounds. The acidic esters described herein can, of course,be neutralized with various compounds, so as to alter the water and oilsolubility factors, as, for example, by the use of trietha olamine,cyclohexylamine, etc. All these variations and derivatives have utilityin various arts where surface-active materials are of value andparticularly are effective as demulsifiers in the resolution ofpetroleum emulsions, as described in Part 3. They may be employed alsoas break-inducers in the doctor treatment of sour crude, etc.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. Hydrcphile synthetic products which are acidic fractional esters ofthe formula R'o5 R"'o ,."1 Rom n'xcoonmi in which the acidic acylradical is that of a polycarboxy acid selected from the group consistingof acyclic and isocyclic polycarboxy acids having not more than 8 carbonatoms and composed of carbon, hydrogen and oxygen of the formula coon oon) in which n is a whole number not greater than 2; and in which thealcohol radical is that of the pentahydroxylated compound 0s( )H]a inwhich R (OH) 5 represents tetramethylolcyclo- 18 hexanol, R' is aradical selected from the class consisting of ethylene and butyleneradicals, n" is an integer not greater than 10, including zero, (R0) isthe divalent propylene oxide radical and n is a number so selected thatthe molecular weight of [RO5(RO),."][(RO),.H]5

is within the range of 1500 to 6000.

2. I-Iydrophile synthetic products which are acidic fractional esters ofthe formula [R'O5(R'O),.-][(OR),,gRC o on i in which the acidic acylradical is that of a dicarboxy acid selected from the group consistingof acyclic and isocyclic dicarboxy acids having not more than 8 carbonatoms and composed of carbon, hydrogen and oxygen of the formula inwhich the acidic acyl radical is that of a polycarboxy acid selectedfrom the group consisting of acyclic and isocyclic polycarboxy acidshaving not more than 8 carbon atoms and composed of carbon, hydrogen andoxygen of the formula:

coon

00011). in which R" is the radical of the polycarboxy acid and n is awhole number not greater than 2; and the alcohol is that of thepentahydroxylated compound in which R (OH) 5 representstetramethylolcyclohexanol and (R0) is the divalent propylene oxideradical and n is a number so selected that the molecular weight of iswithin the range of 1500 to 6000.

4. Hydrophile synthetic products being an acidic fractional ester of thefollowing formula:

in which the acidic acyl radical is that of a dicarboxy acid selectedfrom the group consisting of acyclic and isocyclic dicarboxy acidshaving not more than 8 carbon atoms and composed of carbon, hydrogen andoxygen of the formula:

coon

coon

19 20 in which R" istherr-adical Qfthe -,dicarhoxy:aeid; :5. "Theproduct of :claim '4, wherein the dicarand the alcohol radical isthe-110i the pentahye boxy acid is. .phtha-lic acid. droxyiatedcompound: 6: The product of claim 4;, wherein the idicarboxy acid ismaleic acid. :)mH:l 5 'I. The product of :claim 4, wherein the dicar- 5acid is .succinic "acid. in which H M pres ts t tram t yl y .8. Theproduct of claim 4, wherein the dicarhexanol d R0) s h divalent p ylboxy .acid'is citraconic acid. oxide radical and n is a. numberso.se1eeted-that The product, ofmaim 4 wherein the e o cular W i t Div10 boxy acid is diglyeollic acid.

MELVIN DE GROOTE. R No references cited.

is within the range of 1500 to 6000.

1. HYDROPHILE SYNTHETIC PRODUCTS WHICH ARE ACIDIC FRACTIONAL ESTERS OFTHE FORMULA